How to QUARTILE Data in Excel

What this does

QUARTILE splits a dataset into four equal parts, returning the value at whichever boundary you request. Its second argument is an index from 0 to 4, not a percentage, which trips people who come to it from PERCENTILE. Its practical value is the interquartile range: quartile 3 minus quartile 1 gives the spread of the middle half, and the standard outlier rule flags anything beyond 1.5 IQRs outside those bounds. That is also exactly what a box plot draws, so QUARTILE is how you replicate one numerically. Most people learn this as a sequence of clicks and forget it by next week; learning it as a pattern instead is what lets you apply it to the next, slightly different version of the problem without starting from scratch. That is the difference this page is trying to make. For “quartile data in excel”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That is what makes a workflow that saves repeating the same clicks every week useful in real work: repeatable, auditable, and not dependent on memory or luck.

A worked example

Order values in B2:B200: =QUARTILE.INC(B2:B200, 1) and =QUARTILE.INC(B2:B200, 3) give the quartile bounds, and their difference is the IQR. An upper outlier threshold is =QUARTILE.INC(B2:B200,3) + 1.5*(QUARTILE.INC(B2:B200,3)-QUARTILE.INC(B2:B200,1)). QUARTILE is the numeric basis of the box plot and the standard outlier rule, which makes it the fastest way to describe spread without assuming a distribution. One habit worth forming early: name the cells that hold your inputs, so the formula reads in plain language instead of a string of cell addresses. A reviewer — or you in three months — can then follow the logic without decoding what B7 and D2 were supposed to mean, which is most of what makes a sheet maintainable.

In Google Sheets

Everything above works in Google Sheets too. Excel and Sheets share the formula syntax used here; only the surrounding menus are arranged differently. That portability is deliberate — learn it once and it follows you between the two tools and across Windows and Mac. Keep this page bookmarked for the next time the same question comes up. Better still, repeat the steps once in your own workbook — doing it yourself is what turns a copied answer into something you remember. If you take one thing from this page on “quartile data in excel”, make it the habit rather than the keystrokes: set the problem up with labelled inputs, reference those cells, and let Excel do the recomputing. Bookmark the page for the syntax, but do the example once in a blank sheet and check it against the tool above — five minutes of hands-on practice fixes the method in memory far better than re-reading, and it surfaces the small snags while they are still harmless. After that the technique is genuinely yours: faster than searching for it again, and reliable enough to drop into work that other people depend on.

Common mistakes

• Passing 0.25 instead of 1 — the argument is an index from 0 to 4, not a proportion.
• Using QUARTILE.EXC on small samples where the boundary is undefined, which returns #NUM!.
• Reporting quartiles on a tiny dataset, where they are unstable and a simple sorted list says more.

Frequently asked questions